1. Field of the Invention
The present embodiments relate generally to a flexible external lens for use with an elongate imaging device.
2. Description of Related Art
Using imaging devices to view interior cavities of the human body is common in the medical field. These imaging devices can be elongate and flexible for being passed through a patient's vasculature or other vessel. One such device is an endoscope for performing traditional endoscopic procedures. These devices are generally relatively thin to limit the amount of trauma experienced by a patient when the device is being advanced toward a target viewing site. These devices include a camera disposed at an end of the elongate medical device to allow for viewing at the target viewing site.
Due to the thin and elongate nature of the imaging device, the camera included in the imaging device is also small. The device can include a generally rigid cap at the camera end for protecting the camera from damage due to contact with vessel walls or unintended contact with various parts of the patient's anatomy.
Once positioned near the target viewing site, the elongate and flexible nature of the device allows for the end of the device having the camera to be manipulated or positioned to allow the surgeon to view the interior of the cavity or other vessel. However, the cavity is often filled with blood or other fluid that can obscure the camera's view.
One method for clearing the field of view involves the spraying of a saline or other clear liquid into the area, thereby forcing the blood away from the camera. However, this method is limited in the amount of time that the field of view is clear before the blood or other relatively opaque fluid re-enters the field of view. Moreover, the introduction of the clear fluid may be undesirable in certain medical situations. Additionally, adding a liquid delivery system to the elongate medical device will increase the size of the device, which can increase trauma to the patient during the device's advancement through the body vessel or during the procedure.
Another method for clearing the field of view involves the use of a balloon at the camera end of the device that can be inflated with a clear fluid. When inflated, the balloon will move the opaque fluid in the vessel out of the way. However, the balloon is generally thin to allow for the inflation and deflation, thereby causing it to tend to move side to side, resulting in an inconsistent clear field of view.
Another method involves the use of an elongate and rigid cap on the end of the camera, where the cap is made from a generally transparent material. However, the rigid nature of the cap can result in trauma to the patient in the instance of contact with the vessel wall. Moreover, the rigid cap is generally the same width as the scope to maintain the relatively thin profile of the device. This fixed width limits the width of the clear field of view.
Therefore, there is a need to provide a flexible and elongate imaging device that can maintain a thin profile during advancement through the patient's vasculature that can provide a clear field of view within a body cavity of the patient.